Fusible knife-blade switch having a driving bar for both disconnecting the make-break free end and rotating the hinge end from their respective blade contacts



Oct. 12, 1965 H. H. KOBRYNER 3,211,859

FUSIBLE KNIFE-BLADE SWITCH HAVING A DRIVING BAR FOR BOTH DISCQNNECTING THE MAKE-BREAK FREE END AND ROTATING THE HINGE END FROM THEIR RESPECTIVE BLADE CONTACTS Filed Oct. 10, 1960 3 Sheets-Sheet 1 2a a V4 2? my 0 J6 6 A 6 QM? I,

--r w t W i 5 2 26 3 29 I8 /4 lz g; l6 I7 '15?- A2\ INVENTOR. 3" 6 HERMAN HJLOERVNER,

A ORNEY Get. 12, 1965 KOBRYNER 3,211,859

FUSIBLE KNIFE-BLADE SWITCH HAVING A DRIVING BAR FOR BOTH DISCONNECTING THE MAKE-BREAK E END AND ROTATING THE HINGE END FROM IR RESPECTIVE BLADE CONTACTS Filed Oct. 10, 1960 3 Sheets-Sheet 2 IN V EN TOR H'QhIA/V ll. KOBRYNEIZ (I W A' TTORNEY Oct. 12, 1965 H H. KOBRYNER 3,211,859

FUSIBLE KNIFE-BLADE SWITCH HAVING A DRIVING BAR FOR BOTH DISCONNECTING THE MAKE-BREAK FREE END AND ROTATING THE HINGE END FROM THEIR RESPECTIVE BLADE CONTACTS 2% Y 5 RM z TB M a. Mw WO m Wm m S .r NC a m m s H N a Y Filed 001;. 10, 1960 United States Patent 3,211,859 FUSIBLE KNIFE-BLADE SWITCH HAVING A DRIVING BAR FOR BOTH DISCONNECTING THE MAKE-BREAK FREE END AND R0- TATING THE HINGE END FROM THEIR RESPECTIVE BLADE CONTACTS Herman H. Kobryner, Forest Hills, N.Y., assiguoito 1 Murray Manufacturing Corporation, Brooklyn, N .Y.

Filed Oct. 10, 1960, Ser. No. 61,411 4 Claims. (Cl. 200-114) This invention relates to line connecting means which involves fuses and switches between power and load lines.

Prior line connecting means comprise separate switch and fuse units arranged in series and having individual connections to line terminals.

An object of the invention is to eliminate the need for separate switch and fuse units and to provide, instead, a single novel switch-fuse unit merging switching and fusing functions and requiring only one set of connections to the line.

This aspect of the invention involves a switch incorporating a fuse as one of its elements. More particularly, a knife switch is provided which utilizes a fuse as a connector between switch ends of common switch metal such as copper. The novel switch has make-break and hinge switch ends assembled in mutually insulated relation on a rigid carrier and provided with means to mount a fuse as a bridge between the switch ends. In one embodiment, the switch ends are provided with clips for mounting a ferrule fuse.

In another embodiment, the clips are adapted to mount a knife-ended fuse. Preferably, keepers are associated with the latter form of clips to prevent the fuse from being dislodged.

A fuse-switch unit according to the invention eliminates metal connections required in prior line connecting means for serially connecting separate switch and fuse units and for individually connecting the units to the line. Further, the novel fuse-switch unit eliminates switch metal between the make-break end and the hinge end. Because of the fewer metal connections and parts required by the novel fusible switch and because of its shorter total current path in metal, the heat generated under rated current is less than normal, making it feasible to use switch metal of reduced cross section. All these factors contribute toward lowering the cost of the switch. Further, because of the shorter length of the composite switch and fuse unit compared to the length of serially arranged separate switch and fuse units, a switching device comprising one or a gang of the fusible switches can be set in a smaller enclosure, requiring less wall space; the cost of manufacture also being less.

Another object of the invention is to provide a switching device which permits ready inspection, cleaning and adjustment of contact surfaces. This aspect of the invention involves a mounting for a hinged switch .pole which enables the pole to be removed or replaced without tools and independently of other poles in a multipole switching device. Each switch pole has pin and slot hinge connection with a fixed element in the enclosure for the switching device, the slot being open at one end and angled to allow release of the hinge pin from the slot only when the circuit breaker is in its off position. The enclosure for a switching device comprising a gang of such switch poles includes a cross rod engaged by intermediate portions of the switch poles; the cross rod being operable to drive the switching device to on and off positions. According to the invention, when the circuit breaker is in the off position, any of its switch poles can be dismounted by rocking the pole about the driving cross rod, which serves as a fulcrum, to release the hinge pin from its seating slot.

Other objects of the invention include a novel hinge blade for normally retaining the hinge pin of the switch properly seated in a slot in the hinge blade; quick-break means for the switching device; and means for barring accidental closure of the circuit breaker while the enclosure for the circuit breaker is open.

The above mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a plan View of a typical 3-pole switching device and its enclosure, both constructed according to the invention;

FIG. 2 is a fragmentary section on line 2-2 of FIG. 1 and shows a switch pole at its limit off position;

FIG. 3 is a fragmentary section on line 33 of FIG. 2,

through the hinge end of the switch pole;

FIG. 4 is a partly sectioned perspective of the switch pole in a position approaching on position, portions of the switch pole being broken away to expose other portions;

FIG. 5 is a perspective view of a switch pole in on position and modified to mount a knife type of fuse cartridge; and,

FIG. 6 is a fragmentary section on lines 6-6 of FIG. 1

Referring now to FIG. 1, a 3-pole switching device is shown, usable for example to connect a 3-phase 220 volt power line to load lines. The switching device is mounted in an enclosure 10 provided with a hinged door 11. Each switch pole includes a hinged assembly having a make-break end 12 and a hinge end 13, respectively fastened by bolts 14 to the front and rear ends of a strong and rigid carrier plate 15 of insulating material. The make-break end and the hinge end are similarly constructed, the hinge end being supplemented by a hinge pin 16. Each of these ends comprises paired copper blade jaws 17 backed and reinforced by steel blade springs 18. One jaw 17 and its backing spring 18 are fastened against one side of the insulating carrier 15 by two of the bolts 14, and the companion jaw with its backing spring are fastened against the other side of the carrier by the same two bolts. The paired jaws have facing bosses 17a spaced to clasp a fixed contact blade 19 or 19, with inherent spring pressure reinforced by the clamping pressure of backing springs 18. Blades 19 and 19' are respectively embraceable by the make-break pair of jaws 17 and the hinge pair of jaws. These blades are formed as vertical legs of copper angle pieces mounted on an insulating block 20 fixed to the base of enclosure 10, Terminal connectors 21 are associated with the horizontal legs of the angle pieces.

Blade 19', which serves as a hinge blade, has an inclined slot 19a opened at the outer end to receive hinge pin 16. The hinge pin is supported in the center holes of the bosses 17a in the rear hinge jaws 17 and is confined endwise by the backing spring plates 18 for these jaws. The hinge blade 19' is formed at one side with a raised ring 19b concentric about the rounded bottom of slot 19a and affording a circular depression into which the protuberance or boss 17a of one of the hinge jaws 17 snaps when the hinge pin 16 is seated at the bottom of the slot 19a. The ring 19b thus normally locks the hinge jaws in proper position for holding the hinge pin down on its seat at the bottom of the slot 19a.

Each of the jaws 17 is integrally formed with an upper curved portion 17b serving as one half of a ferrule fuse clip. When two of the jaws are paired at an end of insulating carrier 15, their curved portions 17b extend above the carrier as complemental halves of a flexible fuse clip. A ferrule fuse cartridge 25 is insertable into the front and rear clips 17b to serve as a fusible bridge between the switch ends. Lugs 15a of insulating carrier 15 act as end stops for the cartridge fuse.

Each insulating carrier is formed with an open-ended longitudinal slot 15b for receiving an operating cross bar 26. The cross bar is a crank rod eccentrically mounted by side arms 26a and 26b in opposite sides of enclosure (see FIGS. 1 and .6). Integral with arm 26a and located outside the enclosure 10 is a handle 27. The handle is rockable between limits determined by its engagement with spaced ears of a bracket 28 riveted to the ad acent side of the enclosure. A coil spring 29 extends between the cross bar 26 and an inside wall of the enclosure to act with toggle spring effect for snapping the cross bar to one or the other of the its limit positions. The cross bar passes through the slots b of the three hinged SWlliCh pole assemblies provided in the shown switchingdevice and is rockable by means of the handle 27 to swing the switch pulse to on and off positions.

Any of the switch poles can be dismounted without tools when the switching device is at its off limit. For this purpose, the slot 19a in hinge blade 19 is angled rearwardly and upwardly and is open at its outer end. When the switching device is on or down from its off position, the switch poles and the cross rod 26 are in lower positions. Rocking of a switch pole, therefore, about the rod as a fulcrum in a direction, counterclockwise in FIG. 2, to raise the hinge end 13 is prevented because the slot 19a is at an angle intersecting the attempted arc of movement of the hinge pin 16. Pulling out the pole in the direction of the slot is also impossible due to the shape of the insulating base.

On the other hand, when the switch is off, the rod 26 and switch poles are in upper positions and the relative disposition of the parts is such that leverage applled to a switch pole by the hand for rocking the pole about the rod in a direction to raise the hinge end 13 moves the hinge pin in an arc aligned with the angle of slot 19a, whereby the hinge pin can be moved out of the slot. The switch pole can then be manipulated to shift its slot 15b off the rod 26, leaving the switch pole free to be removed.

A reverse procedure is followed to re-mount the switch pole or to mount a new pole in place. Thus, with the switching device in the OE position, and only in the off position, a switch pole can be manipulated to receive the rod 26 in its slot 15b. The switch pole can then be rocked about the rod in a direction to swing the hinge end 13 down, whereupon the hinge pin 16 will enter the seating slot 19a in hinge blade 19 and the boss 17a on one of the hinge jaws 17 will snap into the recess formed by the raised ring 1% to hold the hinge pm 111 its seat.

Means are provided to bar the inadvertent closure of the switches when the door 11 of enclosure 10 is open. This means includes an upright bar 33 disposed alongside the inside wall of the enclosure opposite the side to which the door is hinged. Bar 33 is pivoted on a stud 34 projecting from the adjacent wall. Riveted to the free side of the bar 33 is a plate 35 integrally formed with an offset upper part 35a. A spring 36 biases the bar 33 and attached plate 35 clockwise (FIG. 6). When the door 11 is open, the bar 33 takes a position, under the influence of spring 36, in which its upper end protrudes above the enclosure, the lower end of the bar striking the bottom of the enclosure to limit the clockwise position of the bar. In this position of the bar, the ledge 35a is in the path of the downward movement of the cross rod 26 from off to on position. Hence, when the door 11 is open, operation of the rod 26 to close the switches is blocked by ledge35a.

When the door is closed, it engages the upper end of bar 33 and rocks the bar and attached plate 35 counterclockwise. The ledge 35a then occupies a position removed from the arc of travel of switch operating cross rod 26. A common snap latch 38 is provided on the enclosure 10 for holding the door 11 closed.

FIG. 5 shows a modification of the composite switchfuse unit, the unit here being shown in the on position. Elements which are essentially the same as in the previously described embodiment are given the same reference designations in FIG. 5.

The jaws 17 at each end are modified in their upper portions to provide flat flexure clips 17b for reception of the knife ends 40a of a knife-ended fuse cartridge 40. This fuse cartridge is heavier than and more adversely affected by inertia during change-overs of the switch from one position to the other and therefore tends to slide out of the fuse clips 17b. To prevent this, retainers in the form of wire bail hooks 41 are pivoted at their lower ends in suitable holes through blades 18 and 17 and their insulating carrier 150. The bails can be swung into positions in which their upper cross-pieces snap into bayonet slots 170 formed in clips 17b above the knife ends 40a. The backing blade springs 18 are here extended upwardly and slightly bent backward to engage the sides of bails 41 with sufficient tension to maintain the bails in their fuse latching positions. In FIG. 5, the bail 41 at the makebreak end is in operative position over a fuse end, while the bail at the hinge end is shown in its release position.

FIG. 5 also shows a modified insulating carrier This carrier, instead of integrally incorporating a slot for passage of driving rod 26, has fastened to it a steel hook 42. The toe of hook 42 is spaced below the carrier 150. A pin 43 is riveted to the hook 42 below the carrier. The vertical leg of a hair-pin torsion wire spring 44 is engaged at its free end in a rear slot 45 of the hook toe. The horizontal leg of the spring 44 is flexed into position over the driving cross rod 26 which engages the upper edge of the toe of the hook. This arrangement causes a quickbreak action of the switch when the rod 26 is rocked upwardly to open the switch. Upon moving the rod 26 upwardly it acts on the horizontal leg of spring 44 to increase its spread from the vertical leg, thereby increasing the spring tension until the rod hits the carrier 150 and pushing it, rocks the switching pole around pin 16 up to the point of disengagement between terminal 19 and switching end 12. In this position, due to the disappearance of frictional forces in the disengaged contact, the tension of the spring is big enough for snaping the switching pole up and causing a quick-break.

While the foregoing description sets forth the principles of the invention in connection with specific apparatus, it is to be understood that this description is made only by way of example and not as a limitation of the scope of the invention as set forth in the objects thereof and in the accompanying claims.

What is claimed is:

1. A knife switch including a hinged switch pole having a make-break free end and an opposite hinge end, and a complementary stationary hinge bracket having hinge pin and slot connection with the hinge end of the switch pole, the slot being closed at the inner end to provide a seat for the hinge pin and being open at the outer end and angled to permit entry or exit of the hinge pin through the open end of the slot only when the switch pole is in off position, the hinge bracket comprising a hinge blade, the hinge end of the switch pole comprising spaced arms for straddling the hinge blade, the hinge pin being supported across said arms and the slot being in said blade for seating the hinge pin when the arms are astride the blade, a driving bar member 'pivotally attached to said switch pole between the free end and hinged end thereof, the switch pole being rotatable about said driving bar member while in off position in a direction to shift the hinge pin out of the open end of the slot and said arms away from the hinge blade, thereby to dismount the switch pole.

2. The invention according to claim 1, said blade having a circular portion concentric with the hinge pin seating end of the slot and at least one of said arms having a complementary circular portion, one of said portions being a depression and the other being a mating protuberance to snap into the depression when the hinge pin is at the seating end of the slot, so as to retain the hinge pin releasably in seated position.

3. A knife switch according to claim 2, said spaced arms of the hinge end being flexible jaws for clasping said hinge blade with inherent spring pressure and being provided with receiving holes for the hinge pin, and reinforcing spring blades backing said arms and engaging the hinge pin ends to maintain the hinge pin in position betwee said jaws.

4. A circuit breaker comprising a gang of knife switches in parallel formation, a box enclosure for the knife switches, each knife switch having spaced front and rear contact elements fixed through insulation to the base of the box and having a hinged switch pole with correspondingly spaced make-break and hinge switch ends, an elongated carrier to which the switch ends are fixed in mutually insulated relation, fuse clips provided on the switch ends for replaceably mounting a fuse cartridge, the hinge end and the associated rear contact element having hinge pin and slot connection, the slot being closed at the inner end to seat the pin and being open at the outer end and angled to permit entry or exit of the pin only while the switch pole is in off position in which the make-break end is away from the associated front contact element, a driving bar mounted eccentrically in opposite sides of the enclosure and extending across the elongated carriers of the gang of switch poles, a handle connected with the driving bar and located outside the enclosure for rocking the driving bar to act on the elongated carriers for swinging the gang of switch poles from off to on position or vice versa, the switch poles and driving bar being in such relative positions in off position that rocking of any switch pole apout the driving bar in a direction to raise the hinge end produces relative movement between the hinge pin and slot, of the hinging connection between the hinge end and associated rear contact element, in a direction aligned with the slot direction so as to cause the hinge pin to leave the slot through its open end while at the same time the hinge end is withdrawing from the associated rear contact element, whereby the switch pole is dismounted, the switch pole being mounted and the hinge connection established by rocking the switch pole about the driving bar, while in otf position, in a direction opposite the aforementioned direction.

References Cited by the Examiner UNITED STATES PATENTS 688,738 12/01 Jones 2001l4 876,910 1/08 Perkins 200-1 14 1,620,814 3/27 Gretchell 2001l4 1,666,979 4/28 Sachs 2001 14 1,757,741 5/30 Sachs 2001l4 -l,9l8,248 7/33 Cook 20067 2,005,686 6/35 Sachs 2001l4 2,007,634 6/35 Broadwell 200-5O 2,193,122 3/40 Crabbs 3394 2,281,052 4/42 Samzelius ZOO- BERNARD A. GILHEANY, Primary Examiner.

RICHARD M. WOOD, ROBERT K. SCI-IAEFER,

Examiners. 

1. A KNIFE SWITCH INCLUDING A HINGED SWITCH POLE HAVING A MAKE-BREAK FREE END AND AN OPPOSITE HINGE END, AND A COMPLEMENTARY STATIONARY HINGE BRACKET HAVING HINGE PIN AND SLOT CONNECTION WITH THE HINGE END OF THE SWITCH POLE, THE SLOT BEING CLOSED AT THE INNER END TO PROVIDE A SEAT FOR THE HINGE PIN AND BEING OPEN AT THE OUTER END AND ANGLED TO PERMIT ENTRY OR EXIT OF THE HINGE PIN THROUGH THE OPEN END OF THE SLOT ONLY WHEN THE SWITCH POLE IS IN OFF POSITION, THE HINGE BRACKET COMPRISING A HINGE BLADE, THE HINGE END OF THE SWITCH POLE COMPRISING SPACED ARMS FOR STRADDLING THE HINGE BLADE, THE HINGE PIN BEING SUPPORTED ACROSS SAID ARMS AND THE SLOT BEING IN SAID BLADE FOR SEATING THE HINGE PIN WHEN THE ARMS ARE ASTRIDE THE BLADE, A DRIVING BAR MEMBER PIVOTALLY ATTACHED TO SAID SWITCH POLE BETWEEN THE FREE END AND HINGED END THEREOF, THE SWITCH POLE BEING ROTATABLE ABOUT SAID DRIVING BAR MEMBER WHILE IN OFF POSITION IN A DIRECTION TO SHIFT THE HINGE PIN OUT OF THE OPEN END OF THE SLOT AND SAID ARMS AWAY FROM THE HINGE BLADE, THEREBY TO DISMOUNT THE SWITCH POLE. 